1. This proposal describes the design, development and usefulness of computer software products enabling industrial scientists to computationally generate protein receptor structures around ligands. These programs will help in the screening of analogs in the design of drugs, hormones, and other commercial products. One long term goal is to reduce the need for use of expensive animal models in drug development. 2. In order to address the problem at hand, the proposed system will use techniques from many different areas of computer science and other disciplines. Software will draw upon techniques from expert systems, data base management systems, statistical pattern recognition dynamic programming and other areas. 3. Commercial applications of the proposed software product include: The design of new small molecular weight drugs in the pharmaceutical industry by rapid screening methods. The design of peptide hormone analogs in the fields of contraception, analgesia, blood pressure, anti coagulants, growth, and others. The design of new antibiotics and antifungals by modelling the bacterial cell wall, and other less understood binding sites, not usually considered to be receptors. The design of new antibody- antigen binding fragments to be utilized in novel testing kits.